The question of whether problems with the social determinants of health that might impact decision-making justify denying eligibility for assisted dying has recently come to the fore in debates about the legalisation of assisted dying. For example, it was central to critiques of the 2021 amendments made to Canada’s assisted dying law. The question of whether changes to a country’s assisted dying legislation lead to descents down slippery slopes has also come to the fore—as it does any time a jurisdiction (...) changes its laws. We explore these two questions through the lens of Canada’s experience both to inform Canada’s ongoing discussions and because other countries will confront the same questions if they contemplate changing their assisted dying law. Canada’s Medical Assistance in Dying law has evolved through a journey from the courts to Parliament, back to the courts, and then back to Parliament. Along this journey the eligibility criteria, the procedural safeguards, and the monitoring regime have changed. In this article, we focus on the eligibility criteria. First, we explain the evolution of the law and what the eligibility criteria were at the various stops along the way. We then explore the ethical justifications for Canada’s new criteria by looking at two elements of the often-corrosive debate. First, we ask whether problems with the social determinants of health that might impact decision-making justify denying eligibility for assisted dying of decisionally capable people with mental illnesses and people with disabilities as their sole underlying medical conditions. Second, we ask whether Canada’s journey supports slippery slope arguments against permitting assisted dying. All data relevant to the study are included in the article. (shrink)